Hello all, We pretty much tried to solve the same issue here with a new API in DMA-IOMMU: https://lore.kernel.org/linux-iommu/20200811054912.GA301@xxxxxxxxxxxxx/T/ Christoph - the user part would be MFC devices on exynos platforms Thanks, Ajay On Wed, Sep 23, 2020 at 12:28 PM Christoph Hellwig <hch@xxxxxx> wrote: > > On Wed, Sep 23, 2020 at 08:48:26AM +0200, Marek Szyprowski wrote: > > Hi Shaik, > > > > I've run into similar problem while adapting S5P-MFC and Exynos4-IS > > drivers for generic IOMMU-DMA framework. Here is my first solution: > > https://lore.kernel.org/linux-samsung-soc/20200918144833.14618-1-m.szyprowski@xxxxxxxxxxx/T/ > > > > > > It allows to remap given buffer at the specific IOVA address, although > > it doesn't guarantee that those specific addresses won't be later used > > by the IOVA allocator. Probably it would make sense to add an API for > > generic IOMMU-DMA framework to mark the given IOVA range as > > reserved/unused to protect them. > > If you want to use IOVA addresses in a device otherwise managed by > dma-iommu we need to expose an API through the dma API. Can you please > include the iommu list in the discussion of your series? > > I don't think using the raw IOMMU API is a very idea in these drivers, > we probably want a way to change the allocator algorithm or hint the > next IOVA and keep using the normal DMA API. Maybe Robin has a better > idea. > _______________________________________________ > iommu mailing list > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/iommu
